Scientists from Germany and Ireland have been studying types of bacteria that are prominent in bogs and sewage plants to research the link between bacteria cells and cells with a nucleus, the eukaryotes. Prior to these studies it was widely suggested that there was perhaps not some intermediate cell, rather a type of fusion of cells to create a new cell. Researchers have found that PVC (Planctomycetes, Verrucomicrobiae, Chlamydiae) bacteria are all types that might be the intermediate step between bacteria and eukaryotes since they are larger and divide more slowly. Further reasearch will be needed to be able to determine if the fusion theory or intermediate theory is more likely.
November 2010 Archives
The gene in question for this study was a2d3 or straightjacket, which is a unique sensory gene because its pathway is in the brain, instead of being in the peripheral nerves, which is usually the "norm" for pain sensory genes. To test this gene they inserted the genetic sequence into fruit flies and exposed the flies to an excessive heat wave, those who were under the influence of the gene failed to move away from the heat. To test where the gene was being affected (brain or peripheral nervous system) they had to isolate the gene, induce pain then observe activity in the mouse, which they observed in the brain. Mapping of other genetic pathways allowed the researchers to conclude it was indeed a2d3 that had the brain pathway. Why we should care is this gene is found in the flies, mice as well as in humans and the mutant of gene a2d3 causes synesthesia which is where one sense triggers the others (including pain). Research on this gene may allow the development of a pain reliever that would be able to counteract the brain pathway and intercept the pain signal.
Found an interesting study by the folks at UCLA...
This study by UCLA looked at brain function based on the two different variants in the CNTNAP2 gene, which has been a suspected gene responsible for Autism. In their study they performed fMRI's on 32 children and looking at the scans they found half of those children were in the "at risk" zone for Autism. The "at risk" zone is when the frontal lobe lights up significantly because its connected to itself immensely but inadequately connected to the rest of the brain. This lack of connectivity leads to a defecit in communication. The team also looked at left/right brain connectivity which allows a person to understand and interpret language. In the at risk children there was a lack of connectivity compared to the non-risk children. An important thing to note, however is that just because a person has an "at risk" gene expression doesn't mean they will be on the Autism scale. The next step to prove that CNTNAP2 is connected directly to Autism will be to try to link that gene mutation to children with language and communication impairments that have been attributed to Autism.
I read an article about the study that was going on to age the "Mitochondrial Eve" by using Mitochondrial DNA. The article said that there are 37 genes that rarely change in the mitochondria, and then there is also a region that varies frequently and quickly. By studying the changes in that they are able to discern some basic evolutionary time periods. The next part of the study is harder for me to understand, they take blood samples from different donors and determine relatedness based on their blood samples, which somehow allows the scientists to age the mitochondrial DNA. It was interesting to read about mitochondrial DNA and that it is only passed down through the mother, and using their processes they aged the mitochondrial DNA they estimate that DNA to have originated 200,000 years ago.
You can view the article here Article